I think SWW was the album the band found "thier sound". Richie started using the natural harmonics on his solos and a few of his other "signature licks" for the first time. SWW was the album where Jon and Richie really started to get their vocal harmonies together. Which IMO is something that defines the sound of the band. The one two punch of their vocals on songs like Wanted and Never Say Goodbye are so powerful that it takes the song to another place. The whole album is great from start to finish.
It's hard me to give it a rating or rank in with the other albums because for me the band have released such a wide array of music that I mostly listen to whatever best suits my mood. If I want party music or a great album to jam along with then this one always gets spun.